The treatment of malignant melanoma has undergone a dramatic evolution in recent years. However, the selection of second－line treatment after initial treatment for unresectable melanomas, such as those that have not responded to immune checkpoint inhibitors (ICI), is very difficult. In fact, the tumor shrinking effect may be reactivated by interspersing radiation therapy or chemotherapy between ICI treatments. We experienced two cases of dacarbazine after nivolumab administration in which regression was seen during dacarbazine administration. The tumor in the first patient, an 83－year－old woman, continued regressing after the switch to nivolumab, and a complete response was achieved. The tumor in the other patient, a 78－year－old man, appeared to continue growing after the switch to nivolumab ; the patient finally died. The tumor burden was greater in the male versus female patient, which we believe caused the difference in efficacy. These findings suggest that dacarbazine as second－line treatment after ICI is an effective treatment choice. However, there are many unclear points about its effectiveness, and the accumulation of further cases is awaited.[Skin Cancer (Japan) 2022 ; 37 : 162－166]

A 75－year－male noted a mass on the left plantar three years prior to consultation. It was incurable with an erosive lesion. Moreover, there was swelling noted in the left inguinal lymph nodes. The specimen showed fascicles of spindle－shaped cells with relatively pale cytoplasm in the dermis. Immunohistochemistry showed positive for S100 and Melan A, while negative for BRAF mutation. Positron emission tomography－computed tomography (PET－CT) showed a high hot uptake in the left inguinal and common iliac lymph nodes. The diagnosis was malignant melanoma. We conducted combined treatments using Mohs paste, nivolumab, and peritumoral injection of interferon－β. A vitiligo appeared on his left leg. The metastatic left inguinal lymph nodes were reduced after undergoing dissection. Six months later, a complete response was achieved. However, there were recurrent subcutaneous tumors on the left plantar aspect, and pink－colored nodes were detected on the left thigh after a few years. Around 80% of tumor cells in resected tumors were positive for PRAME. However, the fusion gene could not be detected.[Skin Cancer (Japan) 2022 ; 37 : 167－172]

Recently, a variety of specific autoantibodies have been associated with dermatomyositis, and each one is known to correlate with different clinical features. Anti－transcriptional intermediary factor 1－γ (Anti－TIF1－γ) antibodies are closely associated with malignancy, and there have been recent reports that they reflect the disease course when they are monitored over time. We examined 84 cases of patients with dermatomyositis that visited our department between May 2017 and November 2021. We studied 26 patients who tested positive for anti－TIF1－γ antibodies.

Sixteen of the 26 patients had malignant tumors, and they tended to have moderate to severe disease with dysphagia and muscle weakness. In the three cases with complete remission of malignancy, antibody titers fluctuated in accordance with the course of treatment. However, in the cases without malignancy, antibody titers decreased with improvement of dermatomyositis symptoms. These results suggest that anti－TIF1－γ antibody fluctuates not only in relation to the severity of dermatomyositis, but also in relation to the severity of malignancy.[Skin Cancer (Japan) 2022 ; 37 : 173－180]

A 60－year－old man presented with a tumor on his penis, that had grown in size, for 2 years. The first examination revealed an erythematous tumor measuring 66 × 53 mm on the back of the penis to the scrotum, and an enlarged left inguinal lymph node was evident. CT and MRI showed infiltration of the left spermatic cord and swelling of bilateral inguinal lymph nodes. A skin biopsy of the tumor yielded a diagnosis of basal cell carcinoma. The tumor was resected with a 1 cm lateral margin, including deep fascia of the penis, and a left inguinal orchiectomy was performed. At the same time, bilateral inguinal lymph node biopsies revealed metastases. Metastatic basal cell carcinoma (MBCC) is rare, however patients with high risk factors for MBCC should be considered for careful follow－up.[Skin Cancer (Japan) 2022 ; 37 : 181－186]

A 37－year－old man noticed a small nodule on his right forearm 7 months before his first visit. The nodule showed enlargement, and he observed new nodules on his forearm and hand. Histopathological evaluation of an excisional biopsy specimen obtained from a nodule revealed findings of epithelioid sarcoma. All nodules were excised with 2－cm margins, and we performed prophylactic lymph node dissection. The surgical margin was negative ; however, we detected micrometastasis in one of the dissected lymph nodes. We administered 3 courses of doxorubicin and ifosfamide as postoperative adjuvant therapy. Epithelioid sarcoma is characterized by not only frequent local recurrence but also lymphatic spread, which is usually uncommon among sarcomas. An epithelioid sarcoma is an extremely rare tumor, and standardized therapy is unavailable ; therefore, large－scale retrospective studies are warranted to gain deeper insight into this malignancy.[Skin Cancer (Japan) 2022 ; 37 : 187－191]

The patient was a 37－year－old male who developed a red nodule on the right forehead in November 2016. Pathological examination revealed dense infiltration of small lymphocytes in the entire dermis layer with intermixed T－cells and B－cells. This lesion was diagnosed as a pseudolymphoma, and disappeared following local steroid injections. The red nodule recurred over the forehead in August 2021. Skin biopsy showed a dense cellular infiltration intermixed with large atypical cells, from the epidermis to the subcutaneous fat tissue, with immunoglobulin heavy chain gene rearrangement. Immunostaining results were CD20(＋), CD79a(＋), bcl－6(＋), bcl－2(－), and MUM－1(－), and the patient was diagnosed with primary cutaneous follicle center lymphoma (PCFCL). No apparent metastasis or other symptoms were observed on PET－CT examination, and local steroid injections and radiotherapy were performed, resulting in the disappearance of the red nodule. PCFCL is a B－cell lymphoma originating in the skin. The condition has a good prognosis, but is sometimes difficult to differentiate from pseudolymphoma. Despite little atypicality in the initial histological findings and good response to treatment, careful observation of the clinical course is desirable.[Skin Cancer (Japan) 2022 ; 37 : 192－196]

We report a case of lymphangiosarcoma in an 81－year－old male patient. Two months prior to his first visit, a 4－cm－sized, slightly indistinct, pale reddish－brown, edematous, infiltrating erythema appeared on his right cheek. He visited his previous physician, who suspected granulomatous disease or a deep cutaneous fungal infection, and performed a fungal culture and skin biopsy. Fungal culture was negative.

Histopathological findings revealed the formation of a slit－like vascular structure by vascular endothelial cells and their proliferation. Few erythrocytes were found inside and outside the blood vessels, and immunostaining was positive for D2－40, leading to the diagnosis of angiosarcoma with lymphangiogenic differentiation. After chemoradiotherapy (a total of 58 Gy of radiation and weekly paclitaxel (80 mg/m2)), the skin rash flattened and showed a tendency to fade. Angiosarcomas can be classified into two types based on their clinical and histological characteristics : hemangiosarcoma (angiosarcoma in the narrow sense) and lymphangiosarcoma.

Lymphangiosarcoma without chronic lymphedema is less hemorrhagic than hemangiosarcoma and tends to have an atypical clinical presentation due to the absence of nodular lesions. Similar to hemangiosarcoma, it is a disease with a poor prognosis and should be treated with caution because it is difficult to diagnose and often appears to be nonmalignant.[Skin Cancer (Japan) 2022 ; 37 : 197－202]

We report a case of huge Merkel cell carcinoma at the left lower eyelid that has been successfully treated with radiation monotherapy in an 80－year－old man. Two months prior to the first visit, an erythematous mass appeared on the left lower eyelid and rapidly enlarged. A mass 8 × 5 cm in size had infiltrated the left upper eyelid. A skin biopsy revealed Merkel cell carcinoma. There was no evidence of lymph node metastasis or systemic multiple organ metastasis. Radiation therapy was selected because surgery was difficult due to the patient’s age, the tumor’s location, and its size. After irradiation with a total of 66 Gy in 33 fractions, the tumor disappeared and complete remission was obtained. One year after irradiation, no recurrence was observed. We experienced a case where radiation was effective even for huge Merkel cell carcinoma, so we report this case with some Japanese literature. [Skin Cancer (Japan) 2022 ; 37 : 203－208]

A 69－year－old male came to our hospital with a chief complaint of a rapidly growing skin tumor on his left forearm. The tumor with crusting at the apex had increased from 12 mm to 30 mm in 3 weeks. After skin biopsy, the patient was diagnosed with keratoacanthoma type squamous cell carcinoma. Three weeks after the initial visit, the size of the tumor had increased to 62 mm, and MRI showed that it had invaded the perimuscular layer. There was no distant metastasis, and the patient underwent total resection, including some muscle layers, but deep margins were positive, so postoperative radiation therapy was administered. Keratoacanthoma type squamous cell carcinoma is classified according to the distribution pattern of the squamous cell carcinoma component ; however, differentiation is often difficult. Since many of these carcinomas have no known cause and can grow rapidly, a biopsy in the form of a complete resection is recommended when clinically suspected.[Skin Cancer (Japan) 2022 ; 37 : 209－212]

A 20－year－old male noticed a skin nodule on his scalp, which gradually increased in size. At his first visit, a 5×3 cm elevated reddish nodule with poor mobility was found over the parietal region. A skin biopsy showed spindle－shaped cell proliferation, CD34 positivity, COL1A1－PDGFB fusion gene. The tumor was diagnosed as dermatofibrosarcoma protuberans with fibrosarcomatous changes. CT and MRI showed a subcutaneous nodule near the skin nodule, and suspected periosteal invasion. Mapping biopsy was done with a margin of 20 mm around the lesion, and one site was positive. Another biopsy was done 10 mm away from the positive site ; this was also reported positive. A further biopsy done 10 mm away from the site was finally negative. A resection operation was performed. Resection margins were negative and there was no recurrence. Mapping biopsy may be useful in determining the extent of resection for dermatofibrosarcoma protuberans of the scalp.[Skin Cancer (Japan) 2022 ; 37 : 213－217]